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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<script>
    function rabbit(n){
        if(n == 1 || n == 2) return 1;
        return rabbit(n-1) + rabbit(n - 2);
    }

    // rabbit(5) =  rabbit(4) + rabbit(3) 
    //           =  rabbit(3) + rabbit(2) +  rabbit(2) + rabbit(1)
    //           =  rabbit(2) + rabbit(1) +  rabbit(2) +  rabbit(2) + rabbit(1)

    // for(var i = 1;i <= 12;i++){
    //     console.log(i, rabbit(i));
    // }

  






</script>
</html>